There is nothing wrong with piercing the ear more than once,
because the basic principle is that it is permissible and there is nothing
to indicate that it is not allowed. But that is on condition that it be in
accordance with the traditions and customs of the people in your country.

It says in al-Mawsoo‘ah al-Fiqhiyyah (29/216): The
basic principle with regard to customs is that which was narrated from Ibn
Mas‘ood (may Allah be pleased with him), who said: Whatever the Muslims
regard as good is good before Allah. And in the books of usool al-fiqh there
is that which indicates that traditions are to be taken into consideration
with regard to fiqh. For example:

The scholars said: “Customs are to regarded as rules… rather
customs are to be taken into consideration if they become prevalent and well
established. There is hardly any book of fiqh or any category of fiqh but
you see custom playing a role in forming some of its rulings.

End quote.

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: If
a woman lives in a country where wearing jewellery in the nose is regarded
as an adornment and beautification, then there is nothing wrong with
piercing the nose in order to wear jewellery in it.

End quote from Majmoo‘ Fataawa Ibn ‘Uthaymeen, 11/
question no. 69

He regarded it as permissible to pierce the nose in order to
wear jewellery in it, if that is the custom of the women in one’s country.

The same applies to piercing the ear more than once in order
to wear jewellery.